1. Field of the Invention
The present invention relates to ratchets and, more particularly, to multiple purpose large heavy duty ratchets.
2. Description of Related Prior Art
Ratchets for applying tension to a cord have been in use for many years and numerous patents have issued directed thereto. U.S. Pat. Nos. 6,068,242, 6,092,791, and Des. 362,614 are representative and are incorporated herein by reference. These ratchets generally include a pair of discs supporting an ingoing and outgoing cord. Upon exerting a pulling force on the outgoing cord, tension is applied to the ingoing cord. To prevent slippage of the cord extending about the pair of discs, there are ridges on the pair of discs in frictional engagement with the cord. Reverse rotation of the pair of discs is generally precluded by use of a pawl engaging a toothed wheel or gear. Upon manual release of the pawl, the pair of discs are free to rotate in either direction. Usually, a hook extends from the body of the ratchet for engagement with an anchor or the like.
Ratchets used to apply tension to webbing have also been available for many years. These ratchets include a spool having a slot formed therein to receive the end of a length of webbing. A pivotally mounted handle includes a spring-loaded slide for engagement with sprockets disposed on either side of the spool. Upon rotation of the handle, the spool rotates and webbing becomes drawn about the spool. Movement of the spool in the opposite direction to release tension on webbing is restricted by a further slide engaging the sprockets. Upon manual engagement of the further slide to withdraw it from engagement with the sprockets, the spool is free to rotate to permit unwinding of the webbing.
Either type of ratchet described above is useable to apply loads usually not in excess of 100 pounds. Moreover, the mechanism of release of the spool requires a certain degree of manual dexterity and strength as a function of the load imposed on the cord or webbing. Thus, these ratchets have limited use with respect to the tension load capability. Furthermore, a significant degree of manual strength may be required to release the spool to permit unwinding of the cord or webbing.